Department of Engg. Physics, Annamalai University, Annamalai Nagar Chidambaram, 608 002, India. sundaraganesan
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Oct 15;74(3):788-97. doi: 10.1016/j.saa.2009.08.019. Epub 2009 Aug 13.
In the present study, structural properties of 3,5-dimethylpyrazole (3,5-DMP) have been studied extensively utilizing density functional theory (DFT) employing B3LYP exchange correlation. The Fourier transform infrared (solid phase and gas phase) and Fourier transform Raman spectra of 3,5-DMP were recorded. The Vibrational frequencies of 3,5-DMP in the ground state have been calculated by using density functional method (B3LYP) with 6-31G(d,p), 6-311G(d,p) and 6-311++G(d,p) as basis sets. Comparison of the observed fundamental vibrational frequencies of 3,5-DMP with calculated results show that 6-311++G(d,p) superior to other basis sets for molecular vibrational problems. Non linear optical NLO behavior of the examined molecule was investigated by the determination of the electric dipole moment mu, the polarizability alpha and the hyperpolarizability beta using the B3LYP/cc-pvdz method. The isotropic chemical shifts computed by (13)C and (1)H NMR analysis also show good agreement with experimental observations. The theoretically predicted FTIR and FT-Raman spectra of the title molecule have been constructed.
在本研究中，利用密度泛函理论（DFT）结合 B3LYP 交换相关，对 3,5-二甲基吡唑（3,5-DMP）的结构性质进行了广泛研究。记录了 3,5-DMP 的傅里叶变换红外（固相和气相）和傅里叶变换拉曼光谱。采用密度泛函方法（B3LYP），使用 6-31G(d,p)、6-311G(d,p)和 6-311++G(d,p)作为基组，计算了 3,5-DMP 在基态下的振动频率。3,5-DMP 的观察到的基本振动频率与计算结果的比较表明，对于分子振动问题，6-311++G(d,p)比其他基组更优越。通过使用 B3LYP/cc-pvdz 方法确定电偶极矩 mu、极化率 alpha 和超极化率 beta，研究了所研究分子的非线性光学 NLO 行为。通过 (13)C 和 (1)H NMR 分析计算的各向同性化学位移也与实验观察结果吻合良好。构建了标题分子的理论预测傅里叶变换红外（FTIR）和傅里叶变换拉曼（FT-Raman）光谱。
